Plug for sealing underground conduits.



PATENTED' APR. 9, 1907.

w. 1.. MUGOWANF PLUG FORSEALING UNDERGROUND GONDUITS.

- APPLICATION FILED 'AIR. 28,1805.

' F/aa v FIG-2 WILLIAM L.

MoGOWAN, OF PHILADELPHIA, PENNSYLVANIA.

PLUG FOR SEALING UNDERGROUND CONDUITS.

Specification of Letters Patent.

Patented April 9, 1907.

Application filed April 28, 1905. Serial No. 257,848.

T0 on whom it may concern:

Be it known that I, WILLIAM L. MoGoWAN, of the city and countyofPhiladelphia and State of Pennsylvania, have invented an Improvement inPlugs for Sealing Underground Conduits, of which the following is aspecification.

My invention has reference to plugs for sealing underground conduits,and consists of certain improvements which are fully set forth in thefollowing specification and shown in the accompanying drawings, whichform a part thereof.

Heretofore it has been customary to seal the ducts of undergroundconduits, either temporarily or permanently, by using a tapering woodenplug, the smaller end of which is driven into the duct. In thisconstruction the larger or butt end of the plug projects to somedistance beyond the edge of the conduit. This makes a very insecureseal, owing to the shape of the plug, which causes it to contact onlywith the outer edge of the duct and because it is easily drawn out ofposition should the outer end be struck or disturbed by somethingfalling upon it. When the plug is disturbed and water rises in any ofthe for the conduit to the height of these plugs, they float out on thesurface of the water and leave the duct open, thereby permitting foreignmatter to enter, with resulting damage and loss. These troubles are morepronounced when a line of conduits is being newly constructed becauseduring a rain-storm the excavation partly or wholly fills with water andthe accidental removal of the plug permits mud and dirt to enter theducts, often requiring that the whole line of conduits shall be takenout, the ducts cleaned, and the conduits relaid, The ends of the ductsare often broken and the sections have to be taken out and replaced withgood ones, the damage being caused by forcing the tapered wooden plugstoo hard into the ends of the ducts, which being of terra-cotta aresomewhat brittle and liable to crack under the strain. Moreover, if thewooden plugs happen to remain in the conduit after becoming soaked withwater they swell and split the conduit, requiring expensive repairs.

The object of my invention is to overcome these existing objections tothe use of the ordinary wooden plugs in ordinary underground-conduitconstruction, whether employed for permanent or temporary purposes,

and in accomplishing this object I employ a metallic plug of simpleconstruction which embodies two parts, one a sealing or face portion andthe other a clamping or retaining portion which extends somewhat intothe conduit.

In carrying out my invention I provide a sheet-metal face-plate havingattached at its rear side a second plate or retaining portion located ata short distance from the faceplate and having its edges so formed thatthey grip or hold upon the interior surface of the duct by friction forthe purpose of hold ing the face-plate into position against the outerface of the conduit and over the entrances to the duct for permanentsealing. This face-plate may be perforated and covered with plasticmaterial.

My invention also comprehends details of construction which, togetherwith the above features, will be better understood by reference to thedrawings, in which Figure 1 is a longitudinal section through one end ofa conduit-section with my improved plug applied thereto. Fig. 2 is aside elevation of the plug removed. Fig. 3 is a rear elevation of same.Fig. 4 is a front elevation of same. Fig. 5 is a view similar to Fig. 1,showing a modified form of my invention used as a permanent seal. Fig. 6is a rear elevation of the plug shown in Fig. 5.

ig. 7 is a sectional elevation of a modified construction elevation, andFig. 9 1s a rear view, of a modified form of my sealing-plug.

A is the conduit-section, and B is the duct thereof. sections A areusually formed of terra-cotta, and the entrance of the duct Bis slightlyflaring at the ends.

is my improved sealing-plug, and, as shown in Figs. 2, 3, and 4,consists of a front plate D, of sheet metal, preferably havingperforations D or other means for handling the plug in withdrawing thesame from the duct and for holding the cement mortar when the plug is tobe used as a permanent seal. These perforations are preferably formed aswhich their edges are exform conical depressions upon the inner faces ofthe plate D adjacent to the apertures. This enables the cement mortar toobtain a more ready hold upon the plate and also to enable it to passthrough the apertures and hold to the plate where apertures come againstthe face of the end of the conduit-section, all of which is clearly ofmy plug. Fig. 8 is a side shown in Fig. 0. To the rear of the front lateand of smaller area is the retainingplate E, consisting of twosheet-metal plates 4 and a disk of rubber H or other elastic or flexiblematerial suitable for the purpose. These plates D and E are securedtogether at a distance apart by spacing rivets or studs F, so that whenthe front plate D is resting against the face of the conduit, theretainingplate E is located some distance within the duct B, as shown inFig. 1. The retainingplate E has the rubber disk H of greater diameterthan the plates E so as to present a flexible rim which is of a diameterslightly greater than the diameter of the duct B. By this means the actof forcing the plate E of the plug into the duct causes the flexible rimto create a friction against the interior walls of the duct and hold theplug in place with the front plate resting against the outer face of theconduit-section In place of making the retaining-plate as shown in Figs.2 and 3, it may be made as shown in Figs. 5 and 6, in which theretainingplate E has its periphery slashed or cut radially and the saidslashed portions bent or curled over to form spring edges H, which ressagainst the interior walls of the duct. This is cheaper and more durablethan the construction shown in Figs. 2 and 3, and while not so tight itwill answer equally well where the outer end of the conduit is coveredwith cement mortar, as at I in Fig. 5, which would ordinarily beemployed where the seal was to be permanent or intended to remain for along period undisturbed. The cement I may attach itself to the frontplate D by entering the apertures 61. The retainingplate E may beattached. to the front plate D in any suitable manner, as block andrivet F.

In Fig. 7 I have shown the face-plate D with its middle portion stampedinward to form a part J, adapted duct, and to this is bolted or rivetedat F the retaining-plate E", which has the slashed or spring edge H.This plate E may be flat, as shown in Fig. 5, or cupped for spacing andcentral rigidity, as maybe desired. The ring K may i F, and is adaptedfor withdrawing the plug from the duct. \Vhile I have shown theseretaining-plates in disk or circular form, I do not restrict myselfthereto, as they may be of any other shape or form so long as theyproduce a friction upon the interior of the duct to hold the front plateagainst the end of the conduit to close the duct.

In Figs. 8 and 9 the front plate D is provided with a rear ring-shapedpart E, held to it by a bolt K, which may be tightened to spread theparts H of this ring to increase its diameter, if so desired. When thisplug is pushed into the duct, the parts H of the retaining-ring pressupon the walls of the by the spacing l duct and hold the front plate Din. position. The shape of the retaining part which enters the duct mayconform to the cross-section of the duct, be it circular or rectangular,or it may be made in any form, so that it only touches a portion of theinterior walls of the duct. The intention is that this invention 1 shallbe applicable to any shape or form of conduit-section which may becommercially p used. \Nhere the front plate is solid or where l sealedwith cement mortar, the shape of the retaining plate or part within theduct is not of importance, but when the front plate D is perforated andthe plug is to be used as a temporary seal it is best that the retainingplate or part shall practically act as a diaphragm across the duct toprevent the influx of mud and dirt.

\Vhile the constructions shown are excellently adapted for thecommercial adaptation of my invention, 1 do not limit myself thereto, asthe details thereof may be modi- :lied without departing from the spiritof the invention.

Having now described. my invention, what I claim as new, and desire tosecure by Letters Patent, is-

1. The combination of a conduit having a duct, with a sealing-plugconsisting of a front plate having a series of perforations and aretaining part frictionally held within the duct for holding the frontplate in position against the front of the conduit, and a covering ofcement mortar over the end of the conduit and front plate and extendininto the perforations thereof so as to bind the rement mortar to theplate.

2. The combination of a conduit having a duct, with a sealing-plugconsisting of a front plate having a series of perforations formed withoutward ly-extending edges forming conical depressions upon the innerface of the plate adjacent to the apertures, and a retainto enter theend of the ing part frictionally held within the duct for holding thefront plate in position against the front of the conduit, and a coveringof cement mortar over the end of the conduit and front plate andextending into the perforal tions thereof so as to bind the cementmortar form an extension of the belt or rivet to the plate.

3. A sealing-plug consisting of a front plate having a series ofperforations formed with outwardly-extending edges forming c0n icaldepressions upon the inner face of the plate adjacent to the apertures,combined with a retaining part of smaller area having a flexible rimadapted to be frictionally held within the duct, and rigid connectionsbetween the front plate and. retaining part whereby they are held apart.

4. A sealing-plug for a conduit consisting of a front plate to fitagainst the end of the conduit, combined with a retaining part of p lesssize so as to enter the duct and having its circumferential edge adaptedto create a friction With the interior Walls of the duct, and means forholding the front plate and retaining part in a firm attached conditionbut so that the circumferential edge of the retaining part issomedistance to the rear of the front plate said means consisting of aseries of rigid studs F distributed between the said front plate andretaining part and each having shoulders near their ends against Whichthe front plate and retaining part respectively rest and riveted beyondthe shoulders at one end to.the front plate and at the area of the ductand having a series of perforations to receive and hold a sealing cementmortar, combined With a spring-acting retaining part secured to the rearof the front plate and having its rim adapted to create a friction withthe interior Walls of the duct at some distance from the front plate soas to act upon the interior Walls of the duct at a l distance from theend of the conduit.

l In testimony of which invention I hereunto set my hand.

WILLIAM L. MGGOWAN.

other end to the retaining part. Witnesses: "5. A sealing-plug for aconduit-duct con- R. M. KELLY, sisting of a front plate of larger areathan the M. J. EYRE.

